Project 4 will examine the effects of hospital stressors and physician reactions to those stressors ("strain") on medication errors. A hospital, like any workplace, embodies forms of work organization, varying workloads, schedules, and shifts which act as stressors affecting physician performance. In addition, the level of stress experienced by physicians, particularly houseofficers, may be affected by interruptions, fragmentation of information, and challenges to professional autonomy. Thus, project 4 will investigate the effects of workplace stressors and houseofficers' level of strain on the frequency and types of medication errors. This research will suggest interventions in hospitals and other health care settings where similar stressors may affect health care workers and thus increase the risk of medication errors. The specific aims of this application are: 1. To determine if, and to what extent, the organization of work within a hospital creates workplace stressors that result in medication errors, i.e., do schedules, shifts, workloads, etc., affect houseofficers' commission of medication errors? 2. To determine if houseofficers' experience of workplace stressors (the cognitive, behavioral, physiological, and psychological "strains") increase the risk of medication errors. 3. To determine how hospital workplace stressors interact with houseofficers' experience of stress ("strain") to influence the risk of medication errors. 4. To determine how hospital workplace stressors interact with houseofficers' baseline psychological profiles to influence the risk of medication errors. Conducted at the Hospital of the University of Pennsylvania, this study will utilize several research measures, including: 1) synthesis and analysis of houseofficers' workloads, shifts, rotations, on-call status, and schedule data from hospitals-the objective stressors; 2) surveys about houseofficers' experiences of workplace stressors-the subjective stressors; 3) surveys about houseofficers' reactions to those stressors ("strain"); 4) a baseline psychometric personality inventory administered at housestaff orientation; and 5) the outcomes for this study--the rate of "near misses" for medication errors detected by the Pharmacy Intervention Program conducted by the hospital's Department of Pharmacy Services and supervised by the Drug Use and Effects Committee. Each houseofficer will be evaluated for the numbers of pharmacy interventions regarding his/her prescriptions, using their total number of inpatient medication orders as the denominator. The goal, as with all the projects, is to suggest feasible interventions most likely to reduce medication errors.